1. Field of the Invention
The present invention relates to a signal receiver and a related voltage compensation method, and more particularly, to a signal receiver and method for providing a compensation current to a first input end of a second-stage circuit of the signal receiver to stabilize its voltage level.
2. Description of the Prior Art
A semiconductor memory can be divided into two categories: a volatile memory, e.g. a dynamic random access memory (DRAM), and a non-volatile memory. The difference between these categories is whether the stored data can be reserved for a long time when external electric power is turned off. The data stored in the DRAM will disappear but the data stored in the non-volatile memory will be preserved.
Please refer to FIG. 1. FIG. 1 is a diagram showing a problem resulted from voltage offsets of a reference voltage in a signal receiver of a memory module according to the prior art. As shown in FIG. 1, VREF represents a reference voltage in a signal receiver of the memory module, offset reference voltages VREF′ and VREF″ respectively represent the offsets of the reference voltage VREF, VIN represents an input signal of the signal receiver, and VOUT represents an output signal after the input signal VIN passes through the signal receiver. If there is no offset exists in the reference voltage VREF, the output signal VOUT is generated after the input signal VIN passes through the signal receiver. If there is an offset exists in the reference voltage VREF, such as the offset reference voltage VREF′ or VREF″, the output signal VOUT′ or VOUT″ is generated after the input signal VIN passes through the signal receiver. As can be known from FIG. 1, if there is an offset exists in the reference voltage VREF, the delay time of the output signal VOUT′/VOUT″ at the rising edge is different from that at the falling edge, which affects the accuracy for accessing data of the memory module.
Hence, how to overcome such problem, resulted from the voltage offsets of the reference voltage in the signal receiver of the memory module, has become an important topic of the field.